3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) that is the improvement of a Universal Mobile Telecommunications System (UMTS) is introduced as 3GPP release 8. The 3GPP LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) in downlink and uses Single Carrier-Frequency Division Multiple Access (SC-FDMA) in uplink. The 3GPP LTE adopts Multiple Input Multiple Output (MIMO) having a maximum of 4 antennas. A discussion on 3GPP LTE-Advanced (LTE-A) that is the evolution of the 3GPP LTE is recently in progress.
Technology introduced in the 3GPP LTE-A includes a carrier aggregation, a relay, etc. A 3GPP LTE system is a single carrier system which supports only one bandwidth (i.e., one component carrier) of {1.4, 3, 5, 10, 15, 20} MHz. However, the LTE-A is introducing multiple carriers employing a carrier aggregation. A Component Carrier (CC) is defined by a center frequency and a bandwidth. A multi-carrier system uses a plurality of CCs each having a smaller bandwidth than the entire bandwidth.
As a plurality of CCs is used, a transmission station (e.g., a base station or a relay) needs to inform a reception station (e.g., a relay or user equipment) that a Physical Downlink Control Channel (PDCCH) over which channel allocation information about a downlink data channel or channel allocation information about an uplink data channel will be transmitted on what CC from among the plurality of CCs.